Where art thou Parkesia Motacilla?


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[ Note that Louisiana Waterthrush (formerly Seiurus motacilla) was recently moved to the new genus Parkesia with Northern Waterthrush, which leaves Ovenbird as the only remaining Seiurus species ]

There has been lots of noteworthy observations in recent days but the most significant development continues to be the late arrival of spring and apparent scarcity of Louisiana Waterthrushes in the study area. The mass of ice pictured below was found yesterday near Little Salmon Lake, Frontenac Prov. Park – a late spring indeed. I’ve now surveyed 23 streams and creeks in and around Frontenac Provincial Park with only a few sightings of the target species to show for it. As the above video shows the sites are in excellent condition owing to high precipitation in late winter and early spring. Water levels and flow are higher than a year ago and insect forage is abundant (particularly the black flies!). Click here for a larger version of the clip.

Lingering ice under cedars
Range Map (Cornell Lab of Ornithology)

The Louisiana Waterthrush has a very limited range in Canada. Breeding occurs primarily in Southern Ontario where remnants of mature deciduous and mixed forest remain. Looking at the map above, the small green dot at the east end of Lake Ontario indicates a cluster of breeding sites corresponding to mature woodlands of the Frontenac Arch and Thousand Islands. There is evidence that this species is expanding northward probably in response to maturing and regenerating forest cover since the logging boom of the 1800s. The population in the Frontenac Arch is essentially the northernmost outpost for this species in North America and somewhat disjunctive from the core range. It has been suggested that Ontario’s population is dependent upon immigration from the source population further south and could therefore be subject to more variable rates of fidelity and productivity. Perhaps 2011 will be a down year for our north-wandering pioneers? We still have a few weeks of surveys to complete and will have a much better handle on the situation by early June – I have a good feeling that results will improve.

Little Salmon Lake

The Louisiana Waterthrush recon work took me to a network of streams flowing to and from Little Salmon Lake in the park’s interior. There are some very promising sites in the area but the relatively young age of the forest is probably not suitable for the species at the present time. Regardless of whether the birds are there or not the effort is still worthwhile to describe and index potential breeding locations for the future. This was my first foray into this area, which made for an interesting day. Sandy beaches like the one pictured above are very scarce in the park.

Pickerel Frog on the beach

The only sunbather I found was this Pickerel Frog (Rana palustris) – a nice find. While not exactly rare they are uncommon compared to their close relative, the very similar and more numerous Northern Leopard Frog (Rana pipiens). Pickerel Frogs are always brown in coloration and have squared spots aligned into two neat rows down their backs. The Northern Leopard Frog is usually green, although sometimes brown too, but have circular, more randomly distributed dark markings.

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Back to the streams…

Frontenac Provincial Park, May 7, 2011

Our fieldwork is well underway in spite of what has been a late arriving and slow moving spring season. The leaf-out is at least a week or two behind schedule and the woods have been unusually quiet for this time of year. However, migrants and returning breeders are appearing in small numbers. A pleasing variety of neotropicals was observed yesterday, which included Wood Thrush, Great Crested Flycatcher and Cerulean, Black-throated Green and Black-throated Blue Warblers. Of particular interest were sightings of Pine Siskin (two occurrences) and Evening Grosbeak – both rare but potentially nesting species in the park. Our official duties at this time of year focus on the Louisiana Waterthrush (Parkesia motacilla), which have been trickling back into Ontario since mid-April. Over the winter a thorough inspection of high resolution aerial photography was conducted, which revealed over 30 potentially suitable nesting sites within our core study area (not including sites visited in 2010). Needless to say I’ve got a ton of walking and canoeing to do in the next few weeks! I will update on our survey results throughout the month of May.

Darvic Colour Bands

In addition to the LOWA reconnaissance we’ve been preparing switch our attention to Prairie Warblers in late May-early June. This year will involve a more extensive ground search of granite barrens in Frontenac Provincial Park for Prairie Warblers. We will also be assessing habitat, nest searching as well as colour banding and tracking males. The project represents our first in-depth look at a breeding species in the Frontenac Arch. The granite barrens scattered along the southern edge of the Canadian Shield in south-central Ontario have received relatively little attention but are important to several species currently in decline such as Common Nighthawk, Field Sparrow, Eastern Towhee and Prairie Warbler.

Prairie Warbler by Seabrooke Leckie

In order to safely capture and mark the birds we will be deploying a mistnet and using a playback/decoy method to lure territorial males. I contemplated various approaches to the construction of a reasonably lifelike decoy, none of which really fit my needs. Fortunately Seabrooke, being both crafty and creative, came up with this little guy, which was handmade from Sculpey – just the ticket ; )

the Nest Files – Louisiana Waterthrush

Female LOWA entering nest

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Louisiana Waterthrush (Seiurus moticilla)

Nidiologicals – Peck and James (1987) and Douglas Robinson (1995)

Habitat
– Gravel bottomed streams flowing through mature deciduous or mixed forest. Also nests in wooded swamp habitats on occasion.
Microhabitat – Nest built in cavities of stream banks, upturned tree roots or fallen logs.
Spring arrival – mid to late April (Ontario)
Average nest height – 0m (always nests on the ground)
Nest builder – male and female
Average # of broods/season – 1 (multiple broods not reported)
Average egg laying date – May 3 – June 12 (New York)
Average clutch size – 5 eggs
Incubation period – average 13 days
Egg colour – Whitish, spotted or blotched with ruddy brown, usually concentrated at large end
Incubation – female
Brown-headed Cowbird host – yes

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Nest building in progress

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Another FBS first – a Lousiana Waterthrush nest! A territorial pair was first located on May 10th at this site but no further breeding evidence was obtained at that time. A followup visit on May 20th revealed both the male and female building this nest in the stream bank above a waterfall. So why the delay? It’s possible that an earlier nest was abandoned but it is more likely that nest construction was delayed after the pair bonded, which is typical according to previous studies (Robinson 1990). On May 20th the pair were observed entering the nest site, which at that time was bascially a mud bowl with a bulky leaf exterior.  The pathway of leaves visible here is a common feature of a Louisiana Waterthrush nest but is not always built. The above photo illustrates this ‘pathway’ constructed of dead leaves, which are noticeably damp and likely collected from the water. The wet leaves and the addition of mud are probably used for adhesion and support of the nest exterior and pathway.

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Nest complete with eggs

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There were four eggs in the nest this morning, which suggests that egg laying began by May 22nd at the latest (1 egg is deposited per day). There might be one more egg still to come as the average clutch size is five (Bent 1953). I watched the female incubate for about an hour before she slipped away for a break. The male was present, he sang on two occasions nearby and made short excursions to the waterfall but never approached the nest. With the female on break, I approached the nest to check its contents and snap a few quick photos.

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Nest contents

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The interior of the nest had transformed since my last visit. What was formerly an excavated mud bowl had become a neatly constructed cup nest lined with fine grasses, rootlets and animal hair.

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This last photo shows the nest site context. This would be considered a fairly exposed nest site for the species. This spot wasn’t on my radar during my initial scan of the banks along the waterfall. There were several other sites that would have been more enclosed, shaded and difficult for non-avians to access. You can just barely see the stream bottom in the lower left corner. Luckily, relocating this nest has always been instantaneous thanks to the convenient tree root pointing to its location! Waterthrushes never fly directly to their nests, instead, they approach the nest by walking from a distance as great as 10m – very typical behaviour for ground nesters. This is nicely demonstrated by the following video of the female at the nest from this morning – whom I could have watched for hours if not for the oppressive heat today. If all goes well, the eggs will hatch in 8-10 days and I’ll be back to check on the family in early June.

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Finally, here is a short video of an adult female LOWA at the nest from today’s visit. Just to avoid any confusion, I should mention that during the video you might hear a Northern Waterthrush singing nearby. The two waterthrush species “get along” very well and exhibit little or no interspecific aggression (Craig 1984). The video can be viewed at higher resolution here.
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Big Salmon Lake by canoe

Common Loons (Big Salmon Lake)

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At nearly five kilometres long, Big Salmon Lake is the largest lake within Frontenac Provincial Park boundaries. The lake has over fifteen kilometres of shoreline and has a maximum depth of 42.3 metres. Bisecting the park along a northeast-southwest axis, Big Salmon has long been a gateway to the Frontenac backcountry and a focal point for early mining and logging industries. Geologically, the lake also marks a divide between two distinct zones – granitic gneiss and marble to the northwest and a large dome of diorite in the southeast.

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Yesterday, I ended up paddling the entire length of Big Salmon to reach two remote streams for the ongoing Louisiana Waterthrush inventory. This long oligotrophic lake was absolutely stunning and a joy to travel across. Steep cliff faces with ancient bonsai-like conifers, Cerulean Warblers singing from mature oak-maple canopies and windswept white and red pines on small rocky islands were just a few of the highlights during the trip.

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Canadian Tiger Swallowtail and Juvenal's Duskywing

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The sightseeing was a nice diversion but my main priority was to find two streams, which to me were nothing more than tiny blue lines on a map. I’ve visited fifteen streams so far this spring and never really know what I am going to encounter. Some streams are pristine, fast moving waterways in steep sloped ravines while others are completely dry and sun drenched. Regardless of their condition, the purpose of the project is to index as many sites as possible to evaluate current stream conditions, habitat preferences, aid future inventories, and to model population parameters of Louisiana Waterthrushes in the area.

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This particular stream was an absolute gem and ‘ticked all the boxes’ for Louisianas in terms of aquatic characteristics as well as slope, canopy closure and presence of suitable nest sites. The meandering stream was teeming with life. My survey of its length revealed a considerable forage base for waterthrushes and very high biodiversity with one glaring exception – no Louisiana Waterthrushes! There was no response to playback following an unsuccessful ground search for the species. This was surprising at first but a broader scan of the site indicated that the mature forest shading the stream was a relatively small patch bordered by younger growth and even small rock barrens. Louisiana Waterthrushes are area sensitive and therefore need large contiguous tracts of mature forest to breed, which would make this site unattractive. Forest succession might make this site suitable for LOWA in the not so distant future.

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The stream itself has been around for quite awhile, evidenced by the erosive passage of water over and through the rocks of the stream. The rectangular finger-shaped rock on the right in the photo above has water passing through it and looks oddly man-made. I’ve uploaded a short video clip of this interesting feature below.

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Green Frog

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Last but not least, a Green Frog (Rana clamitans), one of the many inhabitants of the stream. This fellow was sitting in the middle of the watercourse, faced upstream. Maybe this frog is just chillin’ but I think this might be an excellent way to catch some lunch – let the stream bring it right to you.

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I am starting to run out of accessible waterthrush sites but still have a few more left to visit before the whirlwind of our other breeding bird work begins in early June. I will miss these shady ravines….

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